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A brand new green coating technology for realizing the regulation of spherical propellant energy release process

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Defence Technology（防务技术） 2024年第6期36卷 78-94页

作者： Wenhao Fan yajun Ding Zhongliang Xiao School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing210094China Key Laboratory of Special Energy Materials Nanjing University of Science and TechnologyMinistry of EducationNanjing 210094China

To achieve the controllable release of energy of nitrocellulose-based propellants,this paper combines the cellulose-based nanocomposites aqueous coating(Surelease®-NC)with fluidized bed coating equipment to successfully prepare the coated spherical propellant for the first *** effects of fluidized bed coating temperature,air velocity,flow speed and atomization pressure on the adhesion rate,coating integrity and coating uniformity of the coated spherical propellant were investigated,and the preparation of coated spherical propellant with homogeneous size and structural integrity was achieved for the first *** microscopic morphology,chemical structure,water vapor adsorption behavior,combustion performance,and ageing resistance property of the coated spherical propellant were systematically investigated by,Fourier transforms infrared spectroscopy(FTIR),Micro confocal raman spectrometer,field scanning electron microscopy(SEM),dynamic vapor adsorption techniques,and closed bomb test,confirming the surface core-shell structure and the tightly bonded interfacial structure of coated spherical ***,the coated spherical propellant has good hygroscopic,excellent progressive burning and long storage stability.

关键词： Nanocomposites aqueous coating Fluidized bed coating equipment Coated spherical propellant Controllable release of energy Long storage stability

Underwater RGB-D imaging system with millimetric precision

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Science China(Information Sciences) 2024年第10期67卷 383-385页

作者： yajun GAO Yang CONG Xu TANG Mingxue LI State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences University of Chinese Academy of Sciences College of Automation Science and Engineering South China University of Technology

In recent years, underwater fine three-dimensional reconstruction technology has emerged as a focal point in research, exhibiting extensive potential applications, particularly in underwater archaeology and resource e... 详细信息

关键词： SINGLE CAMERA

Recent advances in the biosynthesis of coumarin and its derivatives

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Green Chemical Engineering 2024年第2期5卷 150-154页

作者： Yusong Zou Yuxi Teng Joy Li yajun Yan School of Chemical Materials and Biomedical EngineeringCollege of EngineeringThe University of GeorgiaAthensGA30602USA North Oconee High School BogartGA30622USA

Coumarin and its derivatives,presenting in many organisms(plants,fungi,and bacteria),are critical metabolites composed of fused benzene andα-pyrone *** unique biological and chemical properties,coumarin derivatives possess great technological potential in the agrochemicals,pharmaceuticals,food,and cosmetic *** increasing demand for coumarin derivatives accelerates the research in biological and chemical synthesis to provide stable and scalable sources of ***,the complex structures and unknown pathways have limited the progress in the biosynthesis of coumarin ***,we summarize recent developments and provide a detailed analysis of coumarin derivative biosynthetic pathways in different organisms.

关键词： Coumarin derivatives Biosynthetic pathways Biotransformation Metabolic engineering

Inversion of O_(2. 1.2. μm nightglow emissions: A climatological analysis using satellite Limb-Viewed spectra and Harmonic analysis method

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Earth and Planetary Physics 2024年第4期8卷 632-640页

作者： YiYi Sui yajun Zhu QiuYu Chen MaoSheng He JiYao Xu State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100190China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Hainan National Field Science Observation and Research Observatory for Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China

This study employs a linear inversion algorithm to retrieve volume emission rates(VERs)of molecular O_(2. nightglow at 1.2.μm,utilizing Limb-Viewed spectra obtained from the SCanning Imaging Absorption spectroMeter for Atmospheric for CHartographY(SCIAMACHY)payload on board the Envisat *** retrieved results are compared with VERs data from the SABER payload on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics(TIMED)satellite,exhibiting *** will help to facilitate accurate revelation of spatial distribution and periodic variation in O_(2. *** are extracted monthly within the altitude range of 75-110 km from 2.02.to 2.12.yielding a climatology of spatial and temporal *** meridional structure exhibits two maxima,at the equator and at 45°*** August and October,the VERs exhibit a meridional bimodal structure,with the weaker one above the equator and the stronger one above 45°*** April,the VERs reach their annual ***,harmonic analysis reveals significant temporal variations on different *** emission shows characteristics of annual and semi-annual variation,and a non-linear long-term trend associated with solar cycle activity.

关键词： VERs O_(2.1.2.μm nightglow SCIAMACHY

Paradigm for Determining the Optimal Ultradeep and Superthick Saline Aquifer for High-TDS Mine Water Geological Storage

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Acta Geologica Sinica(English Edition) 2024年第3期98卷 771-785页

作者： LI Xin CHEN Ge XU Zhimin LIU Qi CHEN Tianci SUN yajun School of Resources and Geosciences China University of Mining and TechnologyXuzhouJiangsu 221116China National Professional Central Laboratory of Basic Research on Mine Water Disaster Prevention and Control Technology XuzhouJiangsu 221116China

Saline aquifers are the most popular waste and CO_(2.injection and storage reservoirs *** project proposes that several optimal injection positions should be investigated as hydraulic pressure-focused positions,in order to relieve the high demands of pump *** comprehensive indices(F_(i))representing the injectivity of different burial depths were obtained by using information entropy,based on the mercury injection experimental data of 13 rock *** results demonstrated that the burial depths of No.4,No.1 and No.2.in the Liujiagou Formation were the most suitable positions for hydraulic focused injection,which means the upper 30 m thickness could be regarded as the hydraulic focused range in the saline aquifer with an average thickness of 400 *** addition,some laboratory experiments and in situ tests were carried out for the purpose of certifying and analyzing results,including SEM,XRD,brittleness index and *** results suggested that the rock samples at the No.4,No.1 and No.2.burial depth ranges have loose microstructure,weak cementation,as well as dual pores and *** lithology is mainly quartz and feldspar,but the clay mineral content is high(10%-2.%),which is positive for *** lithology is suitable for hydraulic fracturing to form extended cracks and micro-fissures during high-TDS(total dissolved solids)mine water injection,because of the high brittleness ***,a theoretical and technical framework for high-TDS mine water injection was established,based on operating pilot *** theoretical defects and drawbacks learned from the field practices were summarized and solutions *** research in this study could provide guidance and a paradigm for the inexpensive treatment of high-TDS mine water by injection and storage.

关键词： ultradeep Liujiagou Formation high-TDS mine water optimal hydraulic injection positions information entropy reservoir spatial characteristics

Introducing urea into tirapazamine derivatives to enhance anticancer therapy

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National Science Review 2024年第4期11卷 245-253页

作者： yajun Xu Jianlin Lv Chaoying Kong Ya Liu Kun Wang Zhaohui Tang Xuesi Chen Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of Sciences School of Applied Chemistry and Engineering University of Science and Technology of China

Tirapazamine（TPZ） has been approved for multiple clinical trials relying on its excellent anticancer ***,as a typical hypoxia-activated prodrug（HAP）,TPZ did not exhibit survival advantages in Phase Ⅲ clinical trials when used in combination therapy due to the insufficient hypoxia levels in patients' *** this study,to improve the therapeutic effects of TPZ,we first introduced urea to synthesize a series of urea-containing derivatives of *** urea-containing TPZ derivatives showed increased hypoxic cytotoxicity（9.51-30.85-fold） compared with TPZ,while maintaining hypoxic ***,one of these derivatives,showed 2.-fold higher cytotoxicity than TPZ while maintaining a similar hypoxic cytotoxicity *** highly efficiently deliver TPZP to the tumors and reduce its side effects on healthy tissues,we further prepared TPZP into a nanodrug with fibrin-targeting ability:***4-NPs,a vascular disrupting agent,was used to increase the fibrin level within tumors and exacerbate tumor *** being combined with CA4-NPs,FT11-TPZP-NPs can accumulate in the hypoxia-aggravated tumors and activate sufficiently to kill tumor *** a single-dose treatment,FT11-TPZP-NPs+CA4-NPs showed a high inhibition rate of 98.1% against CT2. tumor models with an initial volume of ～480 mm3and four out of six tumors were completely eliminated;it thereby exerted a significant antitumor *** study provides a new strategy for improving the therapeutic effect of TPZ and other HAPs in anticancer therapy.

关键词： tirapazamine vascular disrupting agent hypoxia-activated prodrug combretastatin A4 urea

Change of pore water near the freezing front during soil freezing: Migration and mechanisms

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Pedosphere 2024年第4期34卷 770-782页

作者： yajun SHI Wei MA Lianhai ZHANG Chengsong YANG Fei SHANG Cheng CHEN State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Department of Joint NMR Laboratory for Freeze-Thaw Processes in Soils of State Key Laboratory of Frozen Soil Engineering and Suzhou Niumag Analytical Instrument Corporation Lanzhou 730000China

The formation and growth of segregation ice dominate the frost heave during soil freezing,which is closely related to water *** analyze segregation ice during soil freezing for different soils,a freezing-thawing experiment was conducted with Lanzhou loess(LZL)and Qinghai-Tibet Plateau silty clay(QSC)using a novel layered nuclear magnetic resonance *** LZL freezing,the unfrozen water content first increased and then decreased with decreasing temperature near the freezing front,but decreased with decreasing temperature in other layers,whereas during the freezing of QSC,the unfrozen water content in different layers(including the freezing front)decreased with decreased ***,the increased liquid water near the freezing front during LZL freezing was primarily adsorbed *** addition to the temperature gradient,the squeezing action during soil freezing was another important factor affecting water migration,especially at the early stage of soil ***,which of the two factors,squeezing action and temperature gradient,was the dominant one causing water migration depended on soil *** the early stage of soil freezing,the squeezing action had a significant effect on the water migration of LZL,but no significant effect on that of ***,water accumulation of LZL near the freezing front due to squeezing action at the early stage of freezing limited the formation and growth of segregation *** study provided an improved understanding for ice segregation and water migration during soil freezing.

关键词： freezing-thawing experiment frozen soil nuclear magnetic resonance phase transition segregation ice squeezing action unfrozen water water migration

Cu-catalyzed regioselective diborylation of 1,3-enynes for the efficient synthesis of 1,4-diborylated allenes

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Chinese Chemical Letters 2024年第5期35卷 141-144页

作者： Wujun Jian Mong-Feng Chiou yajun Li Hongli Bao Song Yang National Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationCenter for R&D of Fine Chemicals of Guizhou UniversityGuiyang 550025China Strait Institute of Flexible Electronics(SIFE Future Technologies)Fujian Normal UniversityFuzhou 350117China Key Laboratory of Coal to Ethylene Glycol and Its Related Technology State Key Laboratory of Structural ChemistryFujian Institute of Research on the Structure of MatterUniversity of Chinese Academy of SciencesFuzhou 350002China

Borylation of 1,3-enynes with bis(boronate)compounds often ends up with the formation of hydroborylated products,leaving the diborylation of 1,3-enynes for the formation of 1,4-diborylated allenes to be ***,a copper-catalyzed chemo-,regio-,and stereo-selective diborylation of 1,3-enynes for the efficient construction of 1,4-diborylated allenes under base-free conditions was reported.A wide range of 1,3-enynes bearing various functional groups can participant in the reaction and afforded the corresponding 1,4-diborylated allenes in good to excellent yields,which was enabled by the protocol of Bpin to BF3K *** borylcopper species was supposed to selectively attack the C-C triple bond of the 1,3-enynes.

关键词： Copper catalysis Regioselective 1,3-Enynes Borylation Allenes

A Deep Learning Approach to Shape Optimization Problems for Flexoelectric Materials Using the Isogeometric Finite Element Method

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1935-1960页

作者： Yu Cheng yajun Huang Shuai Li Zhongbin Zhou Xiaohui Yuan Yanming Xu College of Architecture and Civil Engineering Xinyang Normal UniversityXinyang464000China Henan Unsaturated Soil and Special Soil Engineering Technology Research Center Xinyang Normal UniversityXinyang464000China College of Intelligent Construction Wuchang University of TechnologyWuhan430223China College of Civil Engineering and Architecture Dalian UniversityDalian116622China Henan International Joint Laboratory of Structural Mechanics and Computational Simulation School of Architecture and Civil EngineeringHuanghuai UniversityZhumadian463000China

A new approach for flexoelectricmaterial shape optimization is proposed in this *** this work,a proxymodel based on artificial neural network(ANN)is used to solve the parameter optimization and shape optimization *** improve the fitting ability of the neural network,we use the idea of pre-training to determine the structure of the neural network and combine different optimizers for *** isogeometric analysis-finite element method(IGA-FEM)is used to discretize the flexural theoretical formulas and obtain samples,which helps ANN to build a proxy model from the model shape to the target *** effectiveness of the proposed method is verified through two numerical examples of parameter optimization and one numerical example of shape optimization.

关键词： Shape optimization deep learning flexoelectric structure finite element method isogeometric